The First Global Map of Atmospheric Ammonia(NH_(3)) as Observed by the HIRAS/FY-3D Satellite

Atmospheric ammonia(NH_(3)) is a chemically active trace gas that plays an important role in the atmospheric environment and climate change. Satellite remote sensing is a powerful technique to monitor NH_(3) concentration based on the absorption lines of NH_(3) in the thermal infrared region. In this study, we establish a retrieval algorithm to derive the NH_(3)column from the Hyperspectral Infrared Atmospheric Sounder(HIRAS) onboard the Chinese Feng Yun(FY)-3D satellite and present the first atmospheric NH_(3) column global map observed by the HIRAS instrument. The HIRAS observations can well capture NH_(3) hotspots around the world, e.g., India, West Africa, and East China, where large NH_(3) emissions exist. The HIRAS NH_(3) columns are also compared to the space-based Infrared Atmospheric Sounding Interferometer(IASI)measurements, and we find that the two instruments observe a consistent NH_(3) global distribution, with correlation coefficient(R) values of 0.28–0.73. Finally, some remaining issues about the HIRAS NH_(3) retrieval are discussed.

FY-3E:The First Operational Meteorological Satellite Mission in an Early Morning Orbit

Fengyun-3 E(FY-3E),the world’s first early-morning-orbit meteorological satellite for civil use,was launched successfully at the Jiuquan Satellite Launch Center on 5 July 2021.The FY-3E satellite will fill the vacancy of the global early-morning-orbit satellite observation,working together with the FY-3C and FY-3D satellites to achieve the data coverage of early morning,morning,and afternoon orbits.The combination of these three satellites will provide global data coverage for numerical weather prediction(NWP)at 6-hour intervals,effectively improving the accuracy and time efficiency of global NWP,which is of great significance to perfect the global earth observing system.In this article,the background and meteorological requirements for the early-morning-orbit satellite are reviewed,and the specifications of the FY-3E satellite,as well as the characteristics of the onboard instrumentation for earth observations,are also introduced.In addition,the ground segment and the retrieved geophysical products are also presented.It is believed that the NWP communities will significantly benefit from an optimal temporal distribution of observations provided by the early morning,mid-morning,and afternoon satellite missions.Further benefits are expected in numerous applications such as the monitoring of severe weather/climate events,the development of improved sampling designs of the diurnal cycle for accurate climate data records,more efficient monitoring of air quality by thermal infrared remote sensing,and the quasicontinuous monitoring of the sun for space weather and climate.

Improvements on global meteorological observations from the current Fengyun 3 satellites and beyond

The Fengyun 3(FY-3)series is the second generation of Chinese sun-synchronous meteorological satellites.The first two,FY-3A and FY-3B,were launched successfully on 27 May 2008 and 5 November 2010,respectively.FY-3A and FY-3B share the same design,equipped with 11 payloads to observe the Earth system,but FY-3A is on a monitoring-orbit and FY-3B is on an afternoon-orbit.As a satellite constellation,FY-3A and FY-3B comprehensively improved meteorological observations in spectral wavelength,spatial coverage,and temporal frequency.This paper summarizes the improvements of the FY-3A and FY-3B satellites.New features,including optical imaging capacity from kilometer to hundred-meter resolution,passive microwave imaging,atmospheric temperature and moisture sounding,atmospheric chemistry remote sensing,and Earth radiation budget measurement,are presented with demonstrations of their use.Instruments scheduled for the FY-3C and beyond are introduced as well.

Variability of Sea Ice from 2008 to 2019 in the Bohai and Northern Huanghai Sea, China and the Relationship with Climatic Factors

Sea ice has important effect on the marine ecosystem and people living in the surrounding regions in winter.However,the understanding on changes of sea ice in the Bohai and northern Huanghai Sea(BNHS),China is still limited.Based on the images from Visible and InfraRed Radiometer(VIRR)onboard Chinese second generation polar-orbit meteorological series satellites FY-3A/B/C,the sea ice areas in the BNHS were extracted from December 2008 to March 2019,the spatio-temporal distribution charac-teristics of sea ice and the relationship between sea ice area and climatic factors were analyzed,then a preliminary sea ice forecast model based on the climatic factors was developed.The results showed that sea ice area in the BNHS in each December was relatively small and rather high sea ice occurrence probability appeared in the offshore areas in Liaodong Bay and northern Huanghai Sea.The sea ice area in January or February each year was the largest,and sea ice occurred in most of areas in Liaodong Bay and northern Huanghai Sea with rather high probability and in some areas in Bohai Bay and Laizhou Bay with relatively high probability.How-ever,the sea ice area in each March was the smallest,and sea ice was even melted completely occasionally,hence with relatively low occurrence probability in Liaodong Bay.As for the inter-annual variability of sea ice in the BNHS during the research period,the sea ice area was largest in winter 2010/11 and smallest in winter 2014/15,and annual sea ice area presented a decreasing trend.The at-mospheric temperature,western Pacific subtropical high(WPSH),Asia polar vortex(APV),Asian monsoon circulation(AMC)and Eurasian monsoon circulation(EMC)were very important climatic factors for sea ice formation and they had significant correlations with sea ice area.Therefore,a preliminary sea ice forecast model was constructed by using eight climatic factors including western Pacific subtropical high area index(WPSHAI),western Pacific subtropical high intensity index(WPSHII),western Pacific subtro-pical high northern boundary position index(WPSHNBPI),Asia polar vortex area index(APVAI),Asian zonal circulation index(AZCI),Asian meridional circulation index(AMCI),Eurasian zonal circulation index(EZCI)and mean minimum atmospheric tem-perature(MMAT).The model was confirmed to have a robust forecast effect by using F-test and validated sample data.The results are useful for monitoring sea ice with remote sensed data and forecasting sea ice conditions by climatic indices.